Baking powder contains baking soda in it, so it can be used as a replacement. Baking powder is probably your best alternative. Baking powder isn’t as strong, so for best results, I would recommend tripling the amount of baking powder that you would use for baking soda. For example, if your recipe calls for 1 teaspoon of baking soda, then use 3 teaspoons of baking powder. Using baking powder may leave you with a saltier taste, so you may want to reduce your salt amount a tiny bit. In the end though, its better to just use baking soda if possible.
There are other options for replacements, but they all have there downsides.
Self Rising Flour
Self Rising Flour can be great, except that if you want to use it to replace baking soda, then you have to adjust the rest of the recipe. You may think that just means using Self Rising Flour instead of All Purpose Flour, but hat is incorrect. You would have to find out if your recipe has an acidic ingredient in it, which for a beginner could be more difficult. Buttermilk would be an example of an acidic ingredient, so you could replace it with regular milk. Other than that it would just be swapping your All Purpose Flour for Self Rising Flour and that covers your baking soda.
Potassium Bicarbonate and Salt or Baker’s Ammonia
I want to be completely honest, I have no idea what either of these are. I would just tell you, that if you don’t know what something is, do you really want to be putting it in your body. This is also something that you may not have in your home already, and if that’s the case, don’t go out and get it, get Baking Soda instead.
While other sites may say other wise, yeast is not the best option for replacing baking soda. While they may be similar, yeast is a living organism. It will also alter the over all taste of your dish.